Beaufort Lagoon source waters - poster
Christina Bonsell and Emily Bristol
Jan 18, 2020
The Beaufort Lagoon Ecosystems Long-Term Ecological Research program (BLE LTER) samples lagoons and coastal areas across the Beaufort Sea coast
We have 4 stations per lagoon system, two in shallow reaches of the lagoon (<1m), and two in deeper areas (>3m). We also sample major freshwater inflows associated with each lagoon.
These lagoons exhibit large variability in salinity over the year.
(no data for EELD1)
What causes this?
To find out, we used salinity and \(\delta ^{18}O\) of lagoon waters sampled in April (full sea ice cover), June (sea ice break-up), and August (open water summer). Explore the data in the plot below:
We used the distinct salinity and \(\delta ^{18}O\) values of sea ice melt (SIM), marine Polar Mixed Layer (PML), and meteoric water (MW) to determine the relative contribution of each endmember to these dynamic lagoons.
\(\delta ^{18}O\) of MW actually varies longitudinally, as seen by the pattern in freshwater inflow samples, here with stations ordered west->east:
| Lagoon | riv_d18O | sd |
|---|---|---|
| Elson | -12.92 | 0.83 |
| Simps | -17.35 | 0.07 |
| Stef | -20.25 | 0.35 |
| Jago | -21.40 | NaN |
We solved the following system of equations for each lagoon water sample:
\(SIM+MW+PML = 1\)
\(5*SIM + 0*MW + 32.1*PML = Salinity\)
\(-2*SIM + x*MW + -3.5*PML = \delta ^{18}O\)
where \(x\) is the mean value for rivers associated with a particular lagoon (see above table)
When each sample is visualized in
At break-up, both SIM and MW usually contribute to the large drops in salinity, but it varies by lagoon system
Figures used in poster
plot mean by lagoon with error bar 
Salinity data vs timepoints of sampling
needs work
mixing plot